The present invention is related to a slat control mechanism for Venetian blinds, including a control assembly, guide sliding assemblies, a linkage drawing plate, and abutting members wherein first rope ladders are suspended between upper and lower beams of a Venetian blind for the abutting position of a plurality of slats in an equal space thereto, and a lift cord is sequentially led through each slat thereof and wound through a pulley seat adapted at one end of the upper beam to extend downwards there-from. The guide sliding assembly is adapted at both corresponding sides of two adjusting seats of the upper beam respectively for retaining a second rope ladder thereby, and the control assembly is mounted at the other side of one adjusting seat thereof for locating an operational cord in opposite to the lift cord of the pulley seat thereof; whereby, the operational cord is simply pulled to actuate the linkage drawing plate and synchronically move a control member of the control assembly and guide sliding members of the guide sliding assemblies connected therewith so as to draw upwards the second rope ladders in a linkage mechanism, facilitating an easier and effortless operation of the present invention to achieve the best using condition thereof.
Please refer to FIG. 1. A conventional blind slat control mechanism is made up of a Venetian blind 10 having a first rope ladder 11 and a second rope ladder 12 sequentially mounted to a plurality of slats 13 and respectively bestriding a lower beam 14 into U-shaped forms. Positioning slide posts 151 and a first and second pulley seats 152, 153 are respectively disposed at both ends of an upper beam 15 for both ends of the first and second rope ladders to wind there-through and extend downwards there-from. In practical use, the first rope ladder 11 is pulled downwards to draw up the odd-numbered or even-numbered slats 13, piling up the slats 13 in pairs to augment the light-passable space as shown in FIG. 2. When the second rope ladder 12 is pulled downwards, the slats 13 will keep gathering up from bottom to top in a sequence. A mounting seat with an adjustment member is adapted inside the upper beam 15 for retaining another rope ladder (without shown in the diagram) to tilt the slats 13 into different angles.
There are some drawbacks to such conventional blind slat control mechanism. First, the first and the second rope ladders 11, 12 are suspended downwards from the same side of the upper beam 15. In practical use, it's easy to confuse the two rope ladders 11, 12 and require a repetition of the operation thereof. Besides, in case pulling force is unevenly applied onto both ends of the first or the second rope ladders 11, 12, the slats 13 can easily get tilted and cause the inconvenience in operation thereof. Second, the first rope ladder 11 is wound through the lower beam 14 thereof. In case of a great pulling force applied thereto, the first rope ladder 11 tends to raise upwards the lower beam 14 and sequentially gather up each slat 13 from bottom to top, losing the function to pile up the slats 13 in pairs, and resulting in the difficult of control in operation thereof. Third, the first rope ladder 11, winding through the inner side of the lower beam 14, must first actuate the lower beam 14 before extending through the first pulley seat 152 to suspend downwards there-from, which can waste quite a lot of efforts and pains in the operation thereof.